Hi, has anyone of you thought of stacking individual frames of timelapse? (e.g. first frame: stack of photos 1 to 10, second frame: stack of photos 2 to 11, third frame: 3 to 12 and so on...)

I know, I sounds crazy, but when you think it through there are bunch of reasons to do that.

1) Reduced noise in shadows...when shooting sunset timelapse, noise is going to appear in shadows no matter what you do, median or average stacking effectively reduces it.
2) Deflicker...also it should remove any flickering left after LRTimelapse. And not just luminance flickering but also color flicker (e.g. in lightened shadows) and tint shift between shots.
3) Motion blur without ND filter. Average stacking of photos creates effect same as long exposure, so it could be used for smoothing up timelapses.
4) Tourist removal. When mean stacking is applied moving objects "disappears". It may be useful in landscape timelapsegraphy on busy locations.

I've did some research and found some useful tools on GitHub for stacking images which could be used to write simple script iterating through timelapse's photos and stacking them.
Maybe headless gimp may be of some use.
Also with few simple commands hugin is capable of aligning images of the timelapse if there is any (e.g. wind or mirror caused shake).

Before I'll start writing this little utility I'd like to ask whether somebody hasn't a better solution or tip to some better useful software.

I searched the internet but didn't find anybody trying to do this, hasn't anyone of you thought about this or tried something similar?

I do it all the time with a full sequence in AfterEffects. Duplicate the layer then move it one frame, then change blending mode. I believe to Lighten. You eliminate birds, bugs, etc...

Why not use the Motion Blur Plus feature when rendering, which does a similar thing, just better and very easily. With the amount settings basically you define the number of images that get blended.

For Windows, there is a tool called Sequator. It can stack images, especially for astro. You can define ground and air, and the tool than will stack them seperatly.
The tool has also a timelapse mode. You can specify the number of images to stack and than does the stacking for each image in the sequence.

I've done it for HDR but found it too time-consuming for the benefit given in most situations.

I've thought about it for macro time lapses, although that would be a ridiculous amount of images... Has anyone tried a focus-stacked macro time lapse?